Device on sewing machines for trimming material

ABSTRACT

Device on sewing machines for trimming edges of the material with a cutter that is mounted for swinging movement on a cutter support adapted to make evading movements and which has an edge disposed in a vertical plane, as well as an angular protecting bridge disposed horizontally above the edge where the cutter support is displaceably mounted in a vertical guide means of a support member arranged on a cutter rocking lever and which is adjustable in height and is held in a central position by means of springs.

1451 Sept. 19,1972

United States Patent Wenz [54] DEVICE ON SEWING MACHINES FOR 10/1933 Capolupo.. ................l12/127 Walsh....;...................

TRIMMING MATERIAL 5/1954 112/127 4/1965 Kleemann et al..........1 12/123 [72] Inventor:

Primary Examiner-H. Hampton Hunter Attorney-Robert l-l. Jacob tern Pfatz, Germany Feb. 29, 1970 [22] Filed:

ABSTRACT Device on sewing machines for trimming edges of the material with a cutter that is mounted for swinging,

211 App]. 196.; 59,107

Foreign Application Priority Data movement on a cutter support adapted to make evading movements and which has an edge disposed in a 611969. Germany 69 31 1246 l vertical plane, as well as an angular protecting bridge disposed horizontally above the edge where the cutter support is displaceably mounted in a vertical guide means of a support member arranged on a cutter rocking lever and which is adjustable in height and is held in a central position by means of springs.

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is secured to a swingingly driven cutter support jour- -nalled to providefor evading movements and which has an edge disposed in'a vertical plane and an angularly offset protective bridge disposed horizontally above the edge.

For cutting the edges of the lower one of two superimposed layers of sewing material closely adjacent 2 disposed one behind the other, in alignment longitudinally with respect to the guide member, which are separated from one another by a bridge provided with a recess in each of which a pressure spring is disposed.

Furthermore, a stud is secured on the bearing member that is perpendicularly directed with respect to the guide member and which, depending on the position of the cutter carrier, projects between the pressure springs into one of the chambers, or into the recess and whose diameter corresponds essentially to the thickness of the bridge. 7

In connection with a trimming cutter that extends outwardly considerably, it may be suitable to journal to the stitch-forming location, a device is known in connection with column 'mounted sewing machines where a support is secured on a rockingly driven cutter shaft 'tha't'isdisposed parallel to the column which support extends .parallel to the cutter shaft to the levelof the supporting'surfacefor the materialat the upper end of thecolumn.

Devices of this type are not suitable for columnar sewing-machines where the looper and the feed wheel are disposed on the same side of the needle.

A further shortcoming of the older device resides in that the trimming cutter cannot make evading movements downwardly. As a result, there is the danger that where there is thickening of the upper layer of the material the protective bridge bumps against the same, and thus damages the material or breaks under certain conditions. t

SUMMARY OF THE INVENTION It is an object of the invention to eliminate these shortcomings and to provide a cutting device whose trimming cutter can avoid obstacles on the material that cannot be separated and which project from the top and from the bottom into the area of the protective bridge, where the edge of the cutting trimmer assumes in any position the saine angular setting and which has a lateral distance relative to the stitch-forming location, which always remains the same.

In accordance with the invention, this is accomplished in that the cutter support is displaceably journalled in a vertical guide means of a supporting the cutter support in the-guide means of the bearing member in a roller bearing, in order to'preclude any possibilities; of wedging of the cutter support in this type of cutting arrangement.

BRIEFDESCRIPTION OF THE DRAWINGS Further details and advantages of the invention will become apparent from the following description of an member disposed for adjustment of its level, upon a v cutter rocking lever and is held in a center position by means of springs.

Due to the parallel position of the guide means for the cutter support with respect to the plane defined by the cutter edge, respectively to the cutting plane, an equal angular position of the cutter edge is insured for any position of the cutter support and an equal lateral spacing of the cutter edge relative to the stitch-forming location, which is entirely independent of the length of the cutter or of the cutter support. The arrangement in accordance with the invention is adapted primarily for such columnar sewing machines, where due to the manner of construction of the columm the distance between the stitch-forming location and the lateral limiting surface of the column that faces the cutting device is especially small.

In accordance with a further feature of the invention, the part of the cutter carrier that is disposed in the guide member has at least two chambers that are embodiment illustrated in the drawings in which FIG. 1 is a partial sectional view of the material supporting column provided with the cutting device in accordance with the invention,

FlG. 2 is a perspective illustration of the arrangement of the cutter support provided with the trimming cutter in the bearing member, and I FIG. 3 is a perspective view partly in section showing the resilient joumalling of the cutter support.

In the supporting column 2 for the material being sewnthat is vertically supported on the base plate 1 of the columnar sewing machine, a looper 3 is disposed that is supported for rotation about a vertical axis, which in a known manner reaches through a feed wheel 5 that serves for moving the material and is driven by a wheel 4, and which cooperates at the side of the feed wheel 5 that is remote from the axis of the looper with the needle 6.

The trimming device has a supporting block 7 secured upon the base plate 1 which rests directly against the housing of the supporting column 2 at the side of the needle 6 that is remote from the feed wheel 5. The bearing block 7 supports a cutter rocking lever 8 which extends parallel to the supporting column 2 that is pivotally supported in the bearing block 7 by means of a horizontally offset stud 9. The cutter rocking lever 8 is rockingly operated by a known drive means. Such a drive means is illustrated, for example, in US. Pat. No. 3,176,639, where it serves for operating a cutter drive shaft that rocks about a vertical axis. For operating the cutter rocking lever 8 which turns about a horizontal axis, the drive device merely needs to be coupled by a ball joint connection with the cutter rocking lever 8, while for connecting the drive means with the cutter drive shaft a pivot joint was sufficient. In the upper part of the cutting rocking lever 8 a guide means is provided that extends parallel to the longitudinal axis of the rocking lever 8, in which a bearing member 10 is disposed which is adjustable in height and can be secured in position by means of a screw 1 1.

In a guide channel 12 of rectangular cross-section which likewise extends parallel to the longitudinal axis of the rocking lever 8 of thesupport member -10, a cutter support 14 is slidably mounted which is provided with a correspondingly shaped guide shaft vl3. At the two narrow sides of the guide shaft 13, two each chambers 15 are provided behind one another that extend longitudinally of the shaft 13, which are separated from one another by abridge 17 having a continuous'recess l6 and in each of which one each pressure spring 18 is arranged that rests with its ends under spring pressure against the end surface of the associated chambers 15, respectvely the bridge 17. At the two sides facing the chambers 15, one each stud screw 19 is disposed in the bearing member each of which reaches between the two pressure springs 18 that face it with its stud 20, whose diameter corresponds essentially to the thickness of the bridge '17, but is smaller than the recess protective bridge 24, then the trimming cutter 21 can evade the obstacle in that depending on the position of the obstacle the cutter. support 14 is displaced in the cutter 21 is mounted that has a blade 22 in a vertical plane which extends parallel to the direction of sewing. The edge 23 of this blade is directed obliquely downwardly in the direction of cutting. Above the edge 23 a protective bridge 24 is bent over angularly on the trimming cutter 21 and thus disposed horizontally.

When the trimming cutter 21 is without load, i.e. in absence of vertical setting forces that act upon the trimming cutter 21, the pressure springs 18 hold the cutter support 14 in a central position (FIG. 2) determined by the position of the studs 20. In this position, the studs 20 project into the recess 16 of the bridges 17, and all pressure springs 18 have been expanded within the chambers up to the bridges 17. The position of the central location of the trimming cutter 2,1 is so chosen in relation to the thickness of the lower layer of the material to be cut by displacing the support member 10 in the cutter rocking lever 8 in a manner that the protective bridge 24 rests from below against the edge of the upper layer of the material without exerting any effective force against the material.

If the material has thickened parts, transverseseams or strips of material disposed between layers of material transversely in the direction of sewing which project from the bottom or from the top into the area of the guide 12 upwardly or downwardly against the resiliency of the springs 18 that is effective in that direction. Since the edge 23 and the guide 12 are disposed in two planes parallel to one another, the position of the cutting plane thus remains constant during evading movements of the trimming cutter 21. Thereby the cutting plane in the material is given even appearance throughout the entire length. v

' Having now described the invention with reference to the embodiment illustrated which l claim as my invention is set forth in the appended claims.

I claim:

1. Device for trimmingedgesof material with a trimming cutter on sewing machines of the type having a vertical column, said device comprising a cutter support journalled for rocking movement and supporting a trimming cutter, said cutter having an edge in a vertical plane and an angularly offset, horizontal protective bridge, a cutter rocking lever mounted proximate the achine column a car in member disposes on said ever and suppo ng sal trfinming cutter, gui e means in said carrying member, a guide shaft extending from said carrying member into said guide means, means for adjusting the level of said carrying member and thereby of said cutter, said guide shaft having a bridge member within said guide means, and a spring on opposite sides t I I t 

1. Device for trimming edges of material with a trimming cutter on sewing machines of the type having a vertical column, said device comprising a cutter support journalled for rocking movement and supporting a trimming cutter, said cutter having an edge in a vertical plane and an angularly offset, horizontal protective bridge, a cutter rocking lever mounted proximate the machine column, a carrying member disposed on said lever and supporting said trimming cutter, guide means in said carrying member, a guide shaft extending from said carrying member into said guide means, means for adjusting the level of said carrying member and thereby of said cutter, said guide shaft having a bridge member within said guide means, and a spring on opposite sides of said bridge member operative to maintain said guide shaft and said carrying member in a centered position.
 2. Device in accordance with claim 1 where said guide shaft defines a pair of chambers on opposite sides of said bridge member housing said springs, said bridge member is provided with a recess generally centrally thereof, a stud extending transversely of said carrying member between adjacent ends of said springs, and said shaft having a thickness corresponding generally to the thickness of said bridge. 